1. Field of the Invention
The present invention relates to an electronic apparatus, a connector-connection-state detection method, and a computer program product.
2. Description of the Related Art
In conventional electronic apparatuses that have circuit boards that exchange signals with each other, FFC (flexible flat cable) harnesses and connectors that connect the terminals of the FFC harnesses to circuits are used for connection between the circuit boards. The strength of an FFC is low and the end portions are easily broken. Moreover, conventional electronic apparatuses have a structure in which a lock is pushed down after the connector is inserted. With this structure, a harness may be pulled out during the operation of pushing down the lock; therefore, semi-insertion of a harness easily occurs. In order to solve semi-insertion that occurs in such a situation, for example, a technique is proposed that prevents semi-insertion by punching the tip portion of a harness by using a structure with a hook and pushing down the lock after inserting and fixing the punched tip portion.
In addition, in view of the fact that it is difficult to completely prevent a bad connection as described above that may occur in a connector, a method is proposed that detects the connection state so that when a bad connection occurs, the connection state can be repaired and returned to its normal state as soon as possible (for example, see Japanese Patent Application Laid-open No. 2009-37300). Japanese Patent Application Laid-open No. 2009-37300 describes a connector-connection-state detecting device that detects withdrawal of a connector that connects a control board and loads to be controlled thereby with a harness. This connector-connection-state detecting device performs a detection operation using a CPU (Central Processing Unit) mounted on the control board. Specifically, the connector-connection-state detecting device transmits a pulled-up signal to the end portion of a harness, divides the signal by pulling down the signal in the control board at a harness connection destination with a resistance value that is different for each connector, returns the divided signal to the control board, and detects the divided voltage value by using the CPU. With this detection method (signal voltage detection method), the detected voltage value is different depending on the point at which the connection of a connector is broken; therefore, it is possible to identify the point at which the connection is broken on the basis of the detected voltage value.
However, in the signal voltage detection method described in Japanese Patent Application Laid-open No. 2009-37300, because a different resistance value is set for each of the connectors and the divided voltage largely depends on the smallest resistance value among the resistance values, the width of the threshold voltage used when determining a connector at which the connection is broken becomes extremely narrow. Moreover, because the resistance components that the harnesses and the connectors have also affect the divided voltage as external factors, there is a problem in that the divided voltage easily varies and an extremely high accuracy is required to realize this method when used with a plurality of connectors.
Therefore, there is a need for an electronic apparatus and a connector-connection-state detection method capable of suitably detecting the connection state of each of a plurality of connectors.